Drivers of Functional Trait Variability in Podarcis erhardii, the Aegean Wall Lizard

Species are capable of adapting to new and rapidly changing environmental contexts. An emerging research frontier in ecology and evolutionary biology is predicting the cascading effects of these adaptations on ecological dynamics and ecosystem services. Making these predictions first requires an understanding of how, when, and why traits change. A "functional trait" approach may provide a framework for understanding context-driven changes in traits and their cascading impacts. My dissertation has focused the argument for rapid trait changes in human contexts, and has empirically tested drivers of functional trait changes in the Aegean wall lizard, Podarcis erhardii.;Functional traits are those that mediate a biotic interaction or ecosystem function of interest. Maximum bite capacity is a functional trait in many lizards as it dictates the lizard's ability to capture and consume prey and protect valuable resources from competitors. In chapter 1, I made use of a natural inter-island gradient in P. erhardii bite force across the Cyclade Islands to determine that variation in this functional trait was more related to intra-specific competition than shifts in diet. In chapters 2 and 3 I tested the impact of human-built stone walls and terraces on another lizard functional trait, foraging mode. I found that lizards on walls adopted a relatively sit-and-wait foraging mode, in contrast to lizards in undisturbed habitats, which actively foraged for their prey. I went on to test a predicted syndrome of morphological, behavioral, and performance traits associated with foraging mode. I found that, according to predictions, the sit-and-wait predators had wider heads and longer legs, facilitating jumping, and capturing a higher proportion of active prey.;My final chapter lays out a conceptual argument for the utility of human-dominated settings, specifically cities, for furthering our understanding of these ecoevolutionary dynamics. Because cities are functioning ecosystems that present myriad adaptive drivers, they may serve as replicate macrocosms for understanding how species adapt to new ecological contexts and what effect those adaptations may have on ecological dynamics.;My dissertation has documented substantial variability in several lizard functional traits across biogeographic and anthropogenic contexts. Collectively, this dissertation demonstrates the importance of understanding intraspecific variability on ecological dynamics, makes the case for humans as instigators of functional trait changes, and lays the groundwork for future advances in the study of evolutionary-ecological feedbacks in human-dominated landscapes.